ALKYLATION OF ANILINE WITH METHANOL - CHANGE IN SELECTIVITY WITH ACIDO-BASICITY OF FAUJASITE CATALYSTS

The alkylation of aniline with methanol was carried out at 673 K on X and Y zeolites exchanged with Li, Na, K, Rb and Cs cations. At low tim e-on-stream the X catalysts are more active than the Y ones but they d eactivate more rapidly. The activity and selectivity were shown to be strongly dependent on the acido-basicity. The selectivity may be orien ted towards alkylation on the nitrogen or on the aromatic ring. The st udy made at equal conversion shows that the selectivity is governed by the balance between the basicity of the oxygen atoms of the framework and the Lewis acidity of the cations in the cages. Generally, the mor e basic zeolites (X and Y exchanged with K, Rb or Cs) favour the produ ction of N-alkylates, mainly N-methylaniline. The zeolites with the mo re acidic cations, Li and Na, give rise to C-alkylation (para- or orth o-toluidine and small amounts of 2,4 or 2,6 dimethylaniline and N,N-di methylparatoluidine). The more basic zeolites display a considerable a ging.